If you build it they will come, and eat all the mosquitoes. The University of Florida has a couple of big bat houses near their campus in Down town Gainesville Florida. And they have greatly reduced the amount of night bugs like moths and mosquitos around the campus. Last I saw they had somewhere in the neighborhood of like 3 million bats in the bat houses. The first bat house got so full of bats they built another bat house. That's a lot of bats. The plans for building a bat house can be found on line of course. But they claim if you have a bug problem especially mosquitoes and have the room to build a bat house do it.